As commercial diet was no.t formulated in yellowtail Seriola quinqueradiata culture, raw fish are employed. However, long term feeding of sardine Sardinops melanosticta causes nutritional disease which accompanies retardation of growth and high mortality. In the present study, feeding trial was carried out in order to prevent the nutritional disease.
The nutritional disease raised in young fish less than 250g in initial body weight. The pathological symptoms such as necrosis of the tublar epithelia and numerical atrophy of the hepatopoietic tissue in the kidney, low level of hematocrit and serum albumin, blood corpuscular resistance were not found in the group fed 0.5% of kelp Laminalia digitata meal and/or 1 % of vitamin mixture.
The dietary kelp and vitamin mixture effectively prevented the nutritional disease. While the preventive effect of kelp on the disease could not be explained, the effect seemed to be different from that of vitamin mixture.
